Set the default active class for router links

This makes the selected region in the Splatfest history dropdown appear correctly.

src/web/components/splatoon/SplatfestHistoryDialog.vue

@@ -14,7 +14,7 @@
                             class="font-splatoon2 is-right-tablet"
                             trigger-class="button is-clear font-splatoon2"
                             >
-                            <router-link v-for="region in regions" class="dropdown-item" :key="region.key" :to="region.route">
+                            <router-link v-for="region in regions" class="dropdown-item" :key="region.key" :to="region.route" exact>
                                 {{ region.name }}
                             </router-link>
                         </DropdownBase>

src/web/router.js

@@ -61,6 +61,7 @@ const routes = [
 
 const router = new VueRouter({
     mode: 'history',
+    linkActiveClass: 'is-active',
     routes,
 });